1. Technical Field
The present invention relates to a method for aligning particulate (granular) beads, and more particularly to a bead alignment method for a capillary bead array having beads aligned in a capillary formed on soft resin.
2. Background Art
JP Patent Publication (Kokai) No. 2000-346842 A is mentioned as prior art concerning a bead alignment method of a capillary bead array. The patent document 1 discloses a technology to introduce beads one by one into a capillary. This prior art is a method for producing a probe array, wherein probe-immobilized fine particles are aligned in a capillary or an optical cell in an order determined in accordance with the type of probe. The method comprises the steps of: retaining the fine particles in a narrow introducing tube; releasing the fine particles one by one under control with a solution into a flowing solution; and introducing them into the capillary to align and retain the fine particles with various probes immobilized thereon in the determined order. The document 1 suggests that the beads introduced into the capillary one by one remain aligned in the capillary.
In addition, JP Patent Publication (Kokai) No. 4-354532 A (1992) discloses the invention wherein different microparticles or different groups of microparticles are irradiated with a plurality of laser beams, and trapped and manipulated with the purpose of controlling the microparticles in a non-contact manner. However, the invention of the document 2 relates to a micro-manipulation technique of combining individual beads with each other, where such technique only involves handling 2 to several microparticles at most with forceps. In this way, the technique disclosed in the patent document 2 requires complicated operations and lacks in practicality. Therefore, there has been a demand for a technique to align an extremely large number of beads one- or two-dimensionally for the use of the beads in a capillary.
According to the existing method of the patent document 1 to introduce beads one by one into a capillary, it takes a progressively longer time to produce a bead array as the number of beads to be introduced increases. The time length to produce a bead array is directly linked to production cost thereof. Further, since the bead alignment retention of the existing techniques relies on capillary shape and size, there is a risk that the bead alignment may become disordered in the capillary. The bead alignment retention has a large impact on the accuracy or reliability of experiments using capillary bead arrays.